This is the first time J.J. Abrams has not written the season finale.

Number 47: (hidden and reversed) Hank Foster says that Sydney was logged in at the safe-house where Nadia was being held at 7.22 p.m. (2+2=4; =74).

Number 47: On the document that Sydney read in the end was a name for the project "S.A.B. 47 Project."

Number 47: On the same document there other references, such as "NO. 938 JB/47" and "176847."

Number 47: The initiation date of Project SAB47 is 04/17/75 (Sydney's birthday).

Sydney's full name is revealed to be Sydney Anne Bristow.

Vaughn: (to Sark) You like the electric batons, the injections... I'm not into accessories...

Vaughn: Last time we were together, our roles were reversed. Funny how things happen...
Sark: I'm afraid the irony is lost on me.

(Lauren is disguised as Sydney)
Sark: I must say, your disguise, it addresses a certain proclivity of mine.
Lauren: If this works, I'll happily make your sick little fantasy come true.

Vaughn: Ready to talk?
Sark: (pause) Yes. When I first learned of your wife's true allegiance, I almost felt pity for you. How embarrassing it must've been to learn that the woman you shared your bed with was only using you as an unfortunate means to an end.
Vaughn: I wouldn't do this, if I were you.
Sark: But then, she wasn't sharing your bed lately, was she? She was in mine. Or in my car. Or the elevator. Or a garage. There is one time – this is my favourite – we were engaged in an alley and she called you to tell you she loved you. (Vaughn twists Sark's arm) That woman was deliciously filthy.

Vaughn: (to Sark) I'm not gonna kill you. That would be too easy. But I'll leave you so disfigured that when you walk down the street people will pity you. Lauren is gonna pay for the damage she's done to the people I care about, not for having had an affair with you. I don't give a rat's ass who she's sleeping with. So for the last time: where is she?

Sydney: (about Vaughn) You want him to kill Lauren...
Jack: If he doesn't, it will eat at him like a cancer. The only cure is to end it now. She destroyed Vaughn's life.
Sydney: Vaughn's life. Not yours. This is about what Lauren did to Vaughn, not what mom did to you. I don't know what you've told him or how much of all this you've orchestrated, but in some twisted way you got Vaughn carrying your burden. Trying to get you closure by doing the one thing you never had the chance to do – kill the person who betrayed you.
Jack: I did have a chance. And I didn't take it. And not a day went by that I didn't regret letting her go. Vaughn will feel the same way. He will end up like me. And I love you too much to let that happen.

Vaughn: (to Lauren) I am gonna erase you! I'm gonna remove any evidence you ever existed! You used me. You used my grief, my work, who I am. You took that from me – I'm taking it back!

Lauren: (to Sydney) You think the CIA couldn't find you when you went missing? Or that you learned what happened to you by chance?

Lauren: (to Sydney) But if your mother has really been helping you since she left, why haven't you spoken to her?

Lauren: We're both pawns in the same game. The difference between us is I know who controls me!
Sydney: Who controls me?
Lauren: I guess you'll never know...

Lauren: If you really love her, you'll put the gun down! (Vaughn puts it down) You really are a Boy Scout.

At the hospital, Vaughn can barely breath, but once he reaches Sydney and Lauren, he is breathing fine.

Vaughn is able to leave the hospital, get a plane, and go to Palermo without anyone knowing.

Mission Impossible

Wearing a mask to disguise as someone else is classic Mission Impossible trick.

Lauren: Tell me you know the pass-phrase.
Sark: I do. It's a quote by Friedrich Nietzsche.
Lauren: "God is dead"?
Sark: No, the other one. "Woman was God's second mistake."

Friedrich Wilhelm Nietzsche was a German philosopher, who became one of the most provocative and influential thinkers of the 19th century. Central to Nietzsche's thought was the notion that with the development of the modern secular world the traditional values (represented by Christianity) had lost their power in the lives of individuals, which he expressed in his infamous proclamation "God is dead".

Die Another Day

In this movie, Bond fakes cardiac arrest to get the doctors in, just like Vaughn did in this episode. It also ends the same, too. Both have the person taking the paddles before being shocked and instead shock the 2 doctors and escape out of custody.